Stamp



1 Ju y 19,1927.

s. B. M' cuLLocH STAMP PAD Filed Feb. 11, 1927 ATTORNEY Patented July 19, 1927.

UNITED STATES PATENT OFFICE.

STEWART IB. MOCULLOCH, OF FULLERTON, CALIFORNIA, ASSIGNOR OF ONE-FOURTH TO 0. A. BURCHARD, ONE-FOURTHTO A. BRIGGS, AND 0NE-FOURTH TO J. B. GOIKE,

ALL OF LOS ANGELES, CALIFORNIA.

73mm in.

Application filed February 11,1927. Serial No. 167,458.

. The present invention relates to method and means for inking rubber stamps and the like and pertains more particularly to stamp pads.

In usual devices of this class there is pro-. vided a suitably absorbent base over which a piece of suitable fabric is stretched. It is an objection to such pads that the interstices of the fabric are filled with ink which is continuously exposed to the air. The result is that the ink oxidizes or becomes gummy and closes the pores in the fabric. It also happens that dust accumulates on the surface of the pad and further acts to clog the exposed fabric so that ink does notflow from the absorbent base when it is required. During use, the fabric of such pads wear and fine loosened fibers of the fabric 'accumulate and further clog the interstices ofthe fabric.- V

The invention has for its principal object the provision of. asta-mp pad which will not become clogged and which will have longer life than present types of pads.

- Another object of the invention is to provide a stamp pad in-which the major portion of the ink supply is out of direct contact with the air and in which pad the ink is drawn rapidly to the inking surface only when the stamp is being applied.

Stamp pads have been used in which the inking surface is provided by the nap of long nap material, such as velvet. All materials such as velvet are made up of felting fibers, which when impregnated with ink either absorb or hold the ink in such manner that the ink and nap form a surface similar to that provided by common felt which has been impregnated with ink or other fluid. The inking surfaces of such pads invariably contain too much ink. If there is an ample supply in or on such pad, the stamp is inked too generously, and the type thereof become quickly clogged with too much ink or with the fibers of the material. If the ink supply is slight, the inking surface is not suflicient, and in order to promptly ink a stamp the pad must be struck forcibly by the stamp. Such application of the stamp to the pad results in depression of the pile of the velvet and before long the pile of the velvet is laid down almost horizontally and the resultant'pad is less satisfactory than the more common types of pad in which a compara tively smooth surfaced fabric is employed.

Realizing that it is the peculiar absorbent and felting'qualities of the materials used which renders all present pads impractical,-

I have set about to discover a suitable material for use on stamp pads.

7 It is therefore another object of the in vention to provide a stamp pad in which felting ofthe fibers, clogging ofthe' fabric, and'the exposureof large quantities of the ink at the surface, are all eliminated.

"Wool and cotton, such as. are used in velvets, plushes, velours, etc., are unsuited for stamp pads not only'because. they hold large quantities of ink between the fibers and bea come felted, but they are also unsuited because ink is applied to such pads from the surface. The felted mass of fibers found on the surface of such pads prevents the proper infiltration of newly applied ink. Consequently the applied ink stands on the surface j of the pad or is held in copious quantities -directly-at the surface. It is another object to eliminate this retention of'large quantities of ink at the surface.

I have illustrated my invention by the accompanying drawings, in which I Figure 1 is a plan view of my improved.

pad in one of its. practical embodiments.

Figure 2 is an enlarged detail view in section thereof. 7 1

Figure 3 a further enlarged fragmem tary cross section similar to Fig. 2. Figure L'is'a View in section of a modified construction.

I More specifically, 1n carrying out my invention in the embodlment shown'in Figs. 1 to 3, lnclusive, I employ a sufficiently abi sorbent'base or pad, such as '5. Said base may be of any one or more of the various well known absorbent materials, such as felted or spongy materials; common felt or common sponge rubber being among the materials I suggest to be employed.

Said pad 1s fitted in a suitable holder or cup 6, preferably made of a fluid tight material, such as metal and provided with up- 7 turned sides 7 Over'the surface of this pad myriads of short hairs 9, of the Angora goat,

which are vertically positioned in a backing 10 of suitably pervious fabric. These hairs are collectively arranged in groups or tufts 11. Each hair of a tuft extends downwardly through the fabric and is looped back to rise again vertically through the fabric. Thus each tuft comprises many short and comparatively stiff vertical hairs, all terminating above the backing 10 on a common horizontal plane.

The tufts are spaced apart fromeach other so that the hairs of one tuft are spaced an appreciable distance from the hairs of another tuft. These tufts are sufficiently spaced to prevent capillary action between the tufts. That is to say, ink introduced to the surface of the mohair will not hang in suspension between the tufts, but it may travel freely down to the-backing to be absorbed by the absorbent base.

. It is a peculiarity of Angoragoat hair, particularly when made into a mohair of well spaced tufts, that it is non fe ting even in the presence of ink ,or moisture. Accordingly the hairs always stand erect.

To ink the pad, ink is applied to the surface and freely finds its way down between the tufts, to the absorbent backing. ink does not remain in suspension between the tufts. It is also a peculiarity of mohair of the construction described, that the juxtaposed hairs of a tuft, or rather the tuft con sidered as a whole, offers less capillary attraction thandoes ordinary felt. such as I eu'iploy for the absorbent base. Consequently when ink is introduced to a tuft, the tuft cannot hold or retain the ink against the capillariity of the underlying felt. As a consequence. ink reaching the tuft is drawn by capillarity down to the absorbent base, while ink introduced between the tufts is even more easily drawn down into the absorbent base.

Thus, when my improved pad is inked practically all the ink is drawn down into the absorbent base. Since the ink is drawn into the base and held there until needed, it is apparent that my improved pad does not expose a generous film of ink to the 1 air. asdoes other pads, and the tendency to become gummed with dried ink is reduced to a practical minimum. This tendency for the ink to be drawn from the hairs into the absorbent base is increased by reason of the i'kngora'goat hair having a smoother and harder exterior surface or sheath, than cotton fibers. and wool of other wool producing anin'ials, which fibers and wool are characterized by a rough and broken surface,

arising the fibers and wool to virtually absorb ink and become saturated.

To ink a. rubber stamp or the like with my improved stamp, best results are had by brushing the stamp lightly and substantially Such horizontallyacross the horizontal surface provided by the tufts. As the surface of the type of the stamp comes in contact with the hairs, the ink films on the hairs are attracted to the type. As the type are moved hor izontally across the hairs, the ink applied to the type. As ink is taken from the hairs in supposedly minute films, other ink is drawn from the base along the hairs in the same infinitesimally thin films. Thus ink is actuz'illy drawn out of the absorbent base by the wiping action of the type over the hairs, and in order to obtain efficient inking, it is not. essential that there be any appreciable amount: of ink on the hairs ahm e the backing 10.

Inthe form of the inventionshown in Fig. 4-, there is provided the felt backing 15, and

the foran'iinous or porous layer it; overlying the backing. Such layer may be composed of rubber or other suitable matt-aial. and in this layer the hairs are embedded in groups. Each hair of a group straight and passes from the undei side of the backing through.

the upper surface so that one end of each hair is exposed above the backing. In this form of pad, ink introduced tothe surface flows through the perforations 17 to the pad.

When a stamp is applied to this pad, ink is drawn up through the tufts, both along the sides of the hairs and througl'i the central capillary which is known to exist in hairs of this kind. In this pad, as theother, Angora goathairsare used l'iccause of thcir coinparative strength and erectness.

While I have shown and described speciiic constructions and arrangement of parts, andhave specified certain materials. .1 do not limit n'iyselfto any specific construction. arrangement of parts, or materials. and l may employ any construction, arrangement of parts, or I may emplqvimy material. without enlarging the scope of my invention as set forth in the appended claims.

I claim 1. 1n stamp pad, an absorbcn t lrauc. and a mohair covering over said base: said mohair covering comprising; a pea-tiers i;'it'li ing with Angora goat hairs passii substantially vertically through raid bacl 2. In a stamp pad. an absorbem case. a backing over said base, and hair rising through said backing to form a pile suifire above said backing; said hairs being); of a non felting character and being less al.s"'z'bent than said base: said hairs passing downwardly through said backinginto contact with said absorbent base.

2:3. A pad in claim 2 and in which pad the hair arranged in tufts spaced sufiiciefntly to prevent capillarity between the to ts.

STEWART n. .MoCULLOCH.

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